1. Field of the Invention
The invention relates to copolymers of monomers containing perfluoroalkyl groups, hydrophilic, ionic and non-ionic monomers and also other comonomers. The invention furthermore relates to the preparation of the copolymers and aqueous dispersions of these copolymers and their use for the finishing of textile materials, leather, paper and mineral substrates against the effects of oil, dirt and water.
2. Description of the Related Art
It is known from U.S. Pat. No. 4,127,711, U.S. Pat. No. 4,564,561, U.S. Pat. No. 4,366,299 and U.S. Pat. No. 4,579,924 that copolymers can be prepared from monomers containing perfluoroalkyl groups, hydrophilic, ionic or non-ionic monomers, and if desired, other comonomers.
The disadvantage is that either the dispersions prepared from these copolymers contain solvents which, during application, make specific safety measures necessary because of the relatively low flash point, or the preparation of the dispersions is possible only with the aid of emulsifiers which, on the other hand, in turn decrease the desired effects, or that, in order to guarantee a high oil- and water-repellency, a very high fluorine content is necessary, which on the other hand leads to hardening in the substrates finished therewith. A further disadvantage is the fact that, after finishing with copolymers from the prior art containing perfluroalkyl groups, a thermal aftertreatment compulsorily has to take place in order to guarantee a high oil- and water-repellency. It is admittedly known from U.S. Pat. No. 4,127,711 that a thermal aftertreatment can also take place under relatively mild conditions of 80.degree. C., but this condition is also disadvantageous for certain applications.